I believe Nikon recalled all D810. As soon as you enter the serial number, it will pop-up an affected message. I think Nikon is playing a safe card. However, not all D810 is having issue.

My camera is among the early release patch, 3002xxx. But I do not have issue. I do not test with black screen and increase exposure. I tested it in a practical way that I would capture images for clients. Put on black glass and capture image.